Wall Street Bets a Rally in Riskiest Stocks Has Staying Power

Traders work on the floor of the New York Stock Exchange.Photographer: Michael Nagle/Bloomberg

US small-cap stocks are having something of a moment — and Wall Street doesn’t expect it to end any time soon.

The Russell 2000 Index, home to some of the riskiest stocks in the market because of their strong ties to the business and credit cycles, just ended the longest run of beating large caps since 1996.